JP4331830B2 - Ceramic circuit board - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a ceramic circuit board having metal circuit boards attached to both sides of the ceramic board.
[0002]
[Prior art]
In recent years, a metal circuit board made of copper or the like is bonded to a metallized metal layer deposited on a ceramic substrate through a brazing material such as a silver-copper alloy as a circuit board such as a power module board or a switching module board. Ceramic circuit board obtained by directly joining a metal circuit board made of copper or the like through an active metal brazing material in which titanium, zirconium, hafnium or a hydride thereof is added to a silver-copper eutectic alloy on the ceramic circuit board. Alternatively, a ceramic circuit substrate manufactured by a so-called DBC (Direct Bond Copper) method in which a copper plate is placed on a ceramic substrate and then heated to directly join the ceramic substrate and the copper plate is used.
[0003]
In addition, in order to increase the mounting density of the metal circuit boards, the ceramic circuit boards are bonded to the upper and lower surfaces of the ceramic board, and the space between the upper and lower metal circuit boards is within the through-hole provided in the ceramic board. Electrical connection is made with a brazing material filled in the metal.
[0004]
The ceramic circuit board, for example, a ceramic circuit board in which a metal circuit board made of copper or the like is bonded to a metallized metal layer deposited on the ceramic board via a brazing material is generally an aluminum oxide sintered body, It is made of an electrically insulating ceramic material such as an aluminum nitride sintered body, a silicon nitride sintered body, or a mullite sintered body, and has a metallized metal layer with a predetermined pattern on both upper and lower surfaces, and penetrates in the thickness direction. Prepare a ceramic substrate with holes, and then fill the through holes of the ceramic substrate with a brazing material paste obtained by adding and mixing an organic solvent and a solvent to silver brazing powder (alloy powder of silver and copper). At the same time, a metal circuit board having a predetermined pattern is placed on and abutted on the metallized metal layer with a brazing material such as silver solder interposed therebetween, and then this is heated to a temperature of about 900 ° C. in a reducing atmosphere. And the brazing material paste and brazing material is melted, it is fabricated by respectively bonding a brazing material of silver solder or the like metallized metal layer and the metal circuit plate and the upper and lower surfaces of the metal circuit plate of the ceramic substrate.
[0005]
[Problems to be solved by the invention]
However, in this conventional ceramic circuit board, the metal circuit boards bonded to the upper and lower surfaces of the ceramic board are electrically connected via a brazing material filled in a through hole provided in the ceramic board. In addition, the brazing material obtained by adding an organic solvent and a solvent to silver brazing powder (alloy powder of silver and copper) in the through hole of the ceramic substrate is filled in the through hole provided in the ceramic substrate. After filling the paste, it is performed by heating to a temperature of about 900 ° C. In this case, a large amount of air existing between the silver brazing powders is embraced in the molten silver brazing material and becomes porous, The conduction resistance was as high as 7 to 10 μΩcm in specific resistance. Therefore, in a conventional ceramic circuit board, when a large current exceeding 10 A flows through the metal circuit board and the brazing material in the through hole, the brazing material portion filled in the through hole generates resistance heat, and the heat is soldered on the metal circuit board. However, it has a drawback in that the electronic component cannot be stably operated at a high temperature by acting on an electronic component such as a semiconductor element that is bonded and fixed via an adhesive material such as the above.
[0006]
The present invention has been devised in view of the above-mentioned drawbacks, and its purpose is to effectively prevent the generation of a large amount of heat due to resistance heat generation, and to normally operate electronic components such as semiconductor elements connected to the metal circuit board as appropriate temperatures, It is another object of the present invention to provide a ceramic circuit board that can be stably operated.
[0007]
[Means for Solving the Problems]
Ceramic circuit board of the present invention, the metal columns consisting resistivity in the through-hole causes attached a metal circuit plate so as to close the through-hole on both surfaces of the ceramic substrate from the metallic material 4μΩcm having a through-hole , both ends were is placed in contact with the metal circuit plate, is characterized in that connects the metal circuit plate of the ceramic substrate both sides with the metal column.
[0008]
According to the ceramic circuit board of the present invention, a metal circuit plate which is attached to both surfaces of the ceramic substrate, almost no pores disposed in the through hole of the ceramic substrate, specific resistance of the following metal columns 4μΩcm , it is disposed in a state in which both ends are in contact with the metal circuit plate, since the electrically connected with the metal columns, also occurs the resistance heating in the metal column as a large current of more than 10A on the metal circuit plate and the metal column flows As a result, a large amount of heat is not generated, and as a result, electronic components such as semiconductor elements that are bonded and fixed onto a metal circuit board using an adhesive such as solder are always at an appropriate temperature, and are normal and stable over a long period of time. It can be activated.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 shows an embodiment of a ceramic circuit board according to the present invention, wherein 1 is a ceramic substrate, 2 is a metallized metal layer, and 3 is a metal circuit board.
[0010]
The ceramic substrate 1 has a quadrangular shape, and a through hole 4 penetrating in the thickness direction is formed in a part thereof, and a metal column 5 is inserted into the through hole 4.
[0011]
The ceramic substrate 1 has metallized metal layers 2 deposited on both upper and lower surfaces, and a metal circuit board 3 is brazed to the metallized metal layer 2.
[0012]
The ceramic substrate 1 is made of an electrically insulating material such as an aluminum oxide sintered body, a mullite sintered body, a silicon carbide sintered body, an aluminum nitride sintered body, or a silicon nitride sintered body. In the case of a sintered body, a suitable organic binder, plasticizer, and solvent are added to and mixed with raw material powders such as aluminum oxide, silicon oxide, magnesium oxide, and calcium oxide to form a mud and the mud is well known in the art. A ceramic green sheet (ceramic green sheet) is formed by adopting the doctor blade method and the calender roll method, and then the ceramic green sheet is appropriately punched to have a predetermined shape having a hole to be a through hole 4 Or by firing at a high temperature (about 1600 ° C), or aluminum oxide, etc. An appropriate organic solvent and a solvent are added to and mixed with the raw material powder to prepare the raw material powder, and the raw material powder is formed into a predetermined shape having holes to be through holes 4 by a press molding machine. It is manufactured by firing at a temperature of about 1600 ° C.
[0013]
The ceramic substrate 1 acts as a support member for supporting the metal circuit board 3, and metallized metal layers 2 are formed in a predetermined pattern on both the upper and lower surfaces and the inner wall surface of the through hole 4. A metal circuit board 3 having a predetermined pattern is brazed to the metallized metal layer 2 deposited on the metal plate.
[0014]
The metallized metal layer 2 acts as a base metal layer when the metal circuit board 3 is brazed to the ceramic substrate 1 and is made of a refractory metal material such as tungsten, molybdenum, manganese, etc. For example, an organic binder suitable for tungsten powder A metal paste obtained by adding and mixing a plasticizer and a solvent is preliminarily printed in a predetermined pattern on both the upper and lower surfaces of a ceramic green sheet (ceramic green sheet) to be a ceramic substrate 1 by firing. As a result, the ceramic substrate 1 is deposited on the upper and lower surfaces of the ceramic substrate 1 in a predetermined pattern and a predetermined thickness (10 to 50 μm).
[0015]
The metallized metal layer 2 is formed by depositing a metal having good conductivity such as nickel and gold and having good corrosion resistance and wettability with a brazing material to a thickness of 1 μm to 20 μm by plating. Further, the oxidative corrosion of the metallized metal layer 2 can be effectively prevented, and the brazing between the metallized metal layer 2 and the metal circuit board 3 can be extremely strengthened. Therefore, in order to effectively prevent the oxidative corrosion of the metallized metal layer 2 and to strengthen the brazing between the metallized metal layer 2 and the metal circuit board 3, the surface of the metallized metal layer 2 has good conductivity such as nickel and gold. Thus, it is preferable to deposit a metal having good corrosion resistance and wettability with the brazing material to a thickness of 1 μm to 20 μm.
[0016]
A metal circuit board 3 is attached to the metallized metal layers 2 deposited on the upper and lower surfaces of the ceramic substrate 1 via a brazing material so as to close the through holes 4 provided in the ceramic substrate 1.
[0017]
The metal circuit board 3 is made of a metal material such as copper or aluminum, and is attached to the metallized metal layer 2 deposited on the upper and lower surfaces of the ceramic substrate 1 via a brazing material such as silver brazing.
[0018]
The metal circuit board 3 made of copper, aluminum, or the like has a thickness of, for example, by applying a conventionally known metal processing method such as a rolling method or a stamping method to an ingot (lumb) such as copper or aluminum. A predetermined pattern shape corresponding to the pattern shape of the metallized metal layer 2 is formed at 500 μm.
[0019]
In addition, when the metal circuit board 3 is formed of oxygen-free copper, the oxygen-free copper is not oxidized by the oxygen existing in the copper during the brazing process. The wettability becomes good and the bonding to the metallized metal layer 2 through the brazing material becomes strong. Therefore, the metal circuit board 3 is preferably formed of oxygen-free copper.
[0020]
Further, when the metal circuit board 3 is coated with a metal made of nickel or the like, which has good conductivity, corrosion resistance, and good wettability with a brazing material, by plating. It is possible to effectively prevent the occurrence of oxidative corrosion and to strengthen the electrical connection between the metal circuit board 3 and the external electric circuit and the connection of electronic components such as semiconductor elements to the metal circuit board 3. . Therefore, the metal circuit board 3 is preferably coated with a metal made of nickel or the like, which has good conductivity, corrosion resistance, and good wettability with the brazing material, on the surface thereof.
[0021]
Still further, the metal circuit board 3 is brazed to the metallized metal layer 2 deposited on the ceramic substrate 1 by placing the metal circuit board 3 on the metallized metal layer 2 and, for example, a silver brazing material (silver: 72% by weight, copper: 28% by weight) and brazing material made of aluminum brazing material (aluminum: 88% by weight, silicon: 12% by weight), etc., and then placed on the metal circuit board 3 by 30-100 g. Heat treatment to a predetermined temperature (about 900 ° C. for silver brazing material, about 600 ° C. for aluminum brazing material) in a vacuum or neutral, reducing atmosphere with a load of / cm ² applied. The metallized metal layer 2 and the metal circuit board 3 are joined with the molten brazing material.
[0022]
The ceramic substrate 1 to which the metal circuit board 3 is brazed has metal pillars 5 disposed in the through holes 4, and the metal pillars 5 are brazed to both the upper and lower surfaces of the ceramic substrate 1. It serves to electrically connect the three.
[0023]
The metal column 5 is formed of a highly conductive metal material such as copper (1.7 μΩcm), aluminum (2.7 μΩcm), silver (1.6 μΩcm) having a specific resistance of 4 μΩcm or less. The resistance is as small as 4 μΩcm or less, that is, the conduction resistance of the metal column 5 is small, so that even if a large current exceeding 10 A flows through the metal circuit board 3 and the metal column 5, resistance heat is generated from the metal circuit board 3 and the metal column 5. A large amount of heat is not generated, and as a result, electronic components such as semiconductor elements that are bonded and fixed onto the metal circuit board 3 using an adhesive such as solder are always at an appropriate temperature, and are normal and stable over a long period of time. It can be activated.
[0024]
For example, when the metal pillar 5 is made of copper, the metal pillar 5 is formed in a cylindrical shape by subjecting a copper ingot (lumb) to a conventionally known metal working method such as a rolling method, a punching method, or a drawing method. the provided et the through hole 4 in the substrate 1, metallization has been applied in the through-hole 4 interior wall causes disposed in contact with the metal circuit plate 3 are attached at both ends to the upper and lower surfaces of the ceramic substrate 1 By brazing the metal layer 2 with a brazing material such as silver braze, both ends of the ceramic substrate 1 are in contact with the metal circuit board 3 attached to the upper and lower surfaces of the ceramic substrate 1 in the through hole 4. Be placed.
[0025]
When the metal pillar 5 is formed of oxygen-free copper, the oxygen-free copper is wetted with the brazing material without being oxidized by the oxygen present in the copper surface during brazing. As a result, the bonding property to the metallized metal layer deposited on the inner wall of the through hole 4 of the ceramic substrate 1 through the brazing material becomes strong. Therefore, the metal pillar 5 is preferably formed of oxygen-free copper.
[0026]
If the diameter of the metal column 5 is less than 200 μm, the conduction resistance of the metal column 5 increases, and there is a risk that a large amount of heat is generated due to resistance heating when a large current exceeding 10 A flows. Therefore, the diameter of the metal column 5 is preferably 200 μm or more, preferably 350 μm or more. In particular, if the diameter of the metal column 5 is set to 350 μm or more, even if a large current exceeding 20 A flows through the metal column 5, a large amount of heat due to resistance heat generation is not generated. An electronic component such as a semiconductor element that is bonded and fixed using a material can always be kept at an appropriate temperature, and the electronic component can be operated normally and stably over a long period of time.
[0027]
Thus, according to the above-described ceramic circuit board, electronic components such as semiconductor elements are bonded and fixed to the metal circuit board 3 attached to the upper surface of the ceramic substrate 1 via an adhesive material such as solder and the electronic elements such as the semiconductor elements. When each electrode of the component is electrically connected to the metal circuit board 3 through an electrical connection means such as a bonding wire, the electronic component such as a semiconductor element is mounted on the ceramic circuit board, and at the same time, the metal circuit board 3 is connected to the external electric circuit. When electrically connected to the circuit, an electronic component such as a semiconductor element is connected to an external electric circuit.
[0028]
Next, another embodiment of the present invention will be described with reference to FIGS.
In the figure, the same parts as those in FIG. 1 are denoted by the same reference numerals.
The ceramic circuit board of FIG. 2 has metal circuit boards 3 of a predetermined pattern attached to the upper and lower surfaces of the ceramic board 1 via active metal brazing material 6 and penetrates in the thickness direction provided in the ceramic board 1 at the same time. A metal column 5 is disposed in the hole 4 by attaching its outer surface to the inner wall of the through-hole 4 via the active metal brazing material 6.
[0029]
The metal pillars 5 arranged in the through holes 4 provided in the ceramic substrate 1 are in contact with the metal circuit board 3 at both ends thereof, whereby the metal circuit boards are attached to the upper and lower surfaces of the ceramic substrate 1. 3 is electrically connected through the metal pillar 5.
[0030]
The ceramic substrate 1 having the through holes 4 is made of the same material as that of the above-described embodiment, and is formed into a predetermined shape by the same method.
[0031]
The ceramic substrate 1 has a metal circuit board 3 attached thereto via an active metal brazing material 6 so as to close the through holes 4 provided in the ceramic substrate 1 on both upper and lower sides. It is made of a metal material such as aluminum, and is formed into a predetermined pattern with a thickness of, for example, 500 μm by applying a conventionally known metal processing method such as a rolling method or a punching method to an ingot (lumb) such as copper or aluminum. Is done.
[0032]
If the metal circuit board 3 is formed of oxygen-free copper, the oxygen-free copper is oxidized by oxygen present in the copper when the oxygen-free copper is attached via the active metal brazing material 6. As a result, the wettability with the active metal brazing material 6 is improved and the metal circuit board 3 is firmly attached to the ceramic substrate 1 via the active metal brazing material 6. Therefore, the metal circuit board 3 is preferably formed of oxygen-free copper.
[0033]
The ceramic substrate 1 has metal pillars 5 disposed in the through holes 4, and the metal pillars 5 electrically connect the metal circuit boards 3 brazed to the upper and lower surfaces of the ceramic substrate 1. Make.
[0034]
The metal column 5 is formed of a highly conductive metal material such as copper (1.7 μΩcm), aluminum (2.7 μΩcm), silver (1.6 μΩcm) having a specific resistance of 4 μΩcm or less. The resistance is as small as 4 μΩcm or less, that is, the conduction resistance of the metal column 5 is small, so that even if a large current exceeding 10 A flows through the metal circuit board 3 and the metal column 5, resistance heat is generated from the metal circuit board 3 and the metal column 5. A large amount of heat is not generated, and as a result, electronic components such as semiconductor elements that are bonded and fixed onto the metal circuit board 3 using an adhesive such as solder are always at an appropriate temperature, and are normal and stable over a long period of time. It can be activated.
[0035]
For example, when the metal pillar 5 is made of copper, the metal pillar 5 is formed in a cylindrical shape by subjecting a copper ingot (lumb) to a conventionally known metal working method such as a rolling method, a punching method, or a drawing method. the provided et the through hole 4 in the substrate 1, an active metal brazing material 6 into the through-hole 4 interior wall causes disposed in contact with the metal circuit plate 3 are attached at both ends to the upper and lower surfaces of the ceramic substrate 1 Is attached via.
[0036]
The metal pillar 5 is formed of oxygen-free copper. When the oxygen-free copper is attached in the through hole 4 of the ceramic substrate 1 via the active metal brazing material 6, the copper surface is The wettability with the active metal brazing material 6 is improved without being oxidized by oxygen present in the copper, and the active metal brazing material 6 is firmly bonded to the inner wall of the through hole 4 of the ceramic substrate 1. Therefore, the metal pillar 5 is preferably formed of oxygen-free copper.
[0037]
If the diameter of the metal column 5 is less than 200 μm, the conduction resistance of the metal column 5 increases, and there is a risk that a large amount of heat is generated due to resistance heating when a large current exceeding 10 A flows. Therefore, the diameter of the metal column 5 is preferably 200 μm or more, preferably 350 μm or more. In particular, if the diameter of the metal column 5 is set to 350 μm or more, even if a large current exceeding 20 A flows through the metal column 5, a large amount of heat due to resistance heat generation is not generated. An electronic component such as a semiconductor element that is bonded and fixed using a material can always be kept at an appropriate temperature, and the electronic component can be operated normally and stably over a long period of time.
[0038]
Further, the metal circuit board 3 and the metal pillars 5 are brazed and attached to the upper and lower surfaces of the ceramic substrate 1 and the through holes 4 without using a metallized metal layer by using a metal active brazing material. As the material, when the metal circuit board 3 and the metal pillar 5 are made of copper, a silver-copper eutectic alloy is added with a metal such as titanium, zirconium, hafnium or a hydride thereof in an amount of 2 to 5% by weight. In addition, when the metal circuit board 3 and the metal pillar 5 are made of aluminum, it is preferable to add 2-5% by weight of a metal such as titanium, zirconium, hafnium or a hydride thereof to an aluminum-silicon eutectic alloy. Used for.
[0039]
First, for example, the silver-copper eutectic alloy such as titanium, zirconium, hafnium or the like is attached to the ceramic substrate 1 having the metal circuit board 3 and the metal pillar 5 through-hole 4 using the metal active brazing material. An active metal brazing paste is prepared by mixing an organic solvent and a solvent with a metal or hydride added thereto in an amount of 2 to 5% by weight. Next, the active metal is formed on the upper and lower surfaces of the ceramic substrate 1 and the inner wall of the through hole 4. A brazing paste is applied and applied in a predetermined pattern by adopting a conventionally known screen printing method, and then metal pillars 5 are inserted and disposed in the through holes 4 of the ceramic substrate 1 and on both upper and lower surfaces of the ceramic substrate 1. The metal circuit board 3 is placed on the active metal brazing paste that has been applied by printing, and then is placed in a vacuum or in a neutral or reducing atmosphere at a predetermined temperature (about 9 for copper). Heat treatment at 0 ° C. and about 600 ° C. in the case of aluminum), the active metal brazing material 6 is melted, and the ceramic substrate 1, the metal circuit board 3 and the metal pillars 5 are joined by the melted active metal brazing material 6. Is done by.
[0040]
In the ceramic circuit board, the specific resistance of the metal pillar 5 is as small as 4 μΩcm or less, that is, the conduction resistance of the metal pillar 5 is small, so that a large current exceeding 10 A is applied to the metal circuit board 3 and the metal pillar 5 as in the above-described embodiment. Even if the current flows, a large amount of heat is not generated by the resistance heat generation from the metal circuit board 3 and the metal pillar 5, and as a result, the semiconductor element is bonded and fixed on the metal circuit board 3 using an adhesive such as solder. Such electronic components are always at a suitable temperature, and can be operated normally and stably over a long period of time.
[0041]
Further, in the ceramic circuit board of FIG. 3, a metal circuit board 3 having a predetermined pattern made of copper is attached to the upper and lower surfaces of the ceramic board 1 by the DBC (Direct Bond Copper) method, and at the same time, the thickness direction provided on the ceramic board 1 A metal column 5 is disposed in the through-hole 4 penetrating into the metal circuit board 3 with both ends thereof in contact with the metal circuit board 3.
[0042]
The ceramic substrate 1 having the through holes 4 is made of the same material as that of the above-described embodiment, and is formed into a predetermined shape by the same method.
[0043]
A metal circuit board 3 made of copper is attached by the DBC method so that the ceramic substrate 1 closes the through holes 4 provided in the ceramic substrate 1 on both upper and lower surfaces thereof, and the metal circuit board 3 made of copper is made of copper. By applying a conventionally known metal processing method such as a rolling method or a punching method to the ingot (lumps), a predetermined pattern is formed with a thickness of 500 μm, for example.
[0044]
The metal circuit board 3 is attached to the upper and lower surfaces of the ceramic substrate 1 by placing and contacting the metal circuit board 3 on the upper and lower surfaces of the ceramic substrate 1 so as to close the through holes 4 provided in the ceramic substrate 1. Then, heat treatment is performed at a predetermined temperature (1065 to 1083 ° C.) in a vacuum or in a neutral or reducing atmosphere to form a copper-copper oxide eutectic between the upper surface of the ceramic substrate 1 and the lower surface of the metal circuit board 3. By doing so, it is attached to the surface of the ceramic substrate 1.
[0045]
The metal circuit board 3 made of copper has an oxide film of 0.02 to 0.5 μm formed in advance on its surface, or if the oxygen content is 100 to 2000 ppm, the ceramic substrate 1 and the metal circuit board 3 The copper-copper oxide eutectic becomes easy and the metal circuit board 3 can be bonded and bonded to the ceramic substrate 1 very firmly. Therefore, it is preferable that the metal circuit board 3 made of copper has an oxide film of 0.02 to 0.5 μm formed in advance on its surface, or the oxygen content is set to 100 to 2000 ppm.
[0046]
Further, when the metal circuit board 3 made of copper is coated with a metal made of nickel, which has good conductivity, corrosion resistance, and good wettability with a brazing material, by plating. And electrical connection between the electronic component such as a semiconductor element and an external electric circuit can be made favorable. Therefore, the metal circuit board 3 made of copper is preferably coated with a metal made of nickel, which has good conductivity, corrosion resistance, and good wettability with the brazing material.
[0047]
Further, the ceramic substrate 1 has metal pillars 5 disposed in the through holes 4, and the metal pillars 5 electrically connect the metal circuit boards 3 attached to the upper and lower surfaces of the ceramic substrate 1. Make.
[0048]
The metal column 5 is formed of a highly conductive metal material such as copper (1.7 μΩcm), aluminum (2.7 μΩcm), silver (1.6 μΩcm) having a specific resistance of 4 μΩcm or less. The resistance is as small as 4 μΩcm or less, that is, the conduction resistance of the metal column 5 is small, so that even if a large current exceeding 10 A flows through the metal circuit board 3 and the metal column 5, resistance heat is generated from the metal circuit board 3 and the metal column 5. A large amount of heat is not generated, and as a result, electronic components such as semiconductor elements that are bonded and fixed onto the metal circuit board 3 using an adhesive such as solder are always at an appropriate temperature, and are normal and stable over a long period of time. It can be activated.
[0049]
For example, when the metal pillar 5 is made of copper, the metal pillar 5 is formed into a cylindrical shape by subjecting a copper ingot (lumb) to a conventionally known metal working method such as a rolling method, a punching method, or a drawing method. , is inserted in the the provided et the through-hole 4 the ceramic substrate 1, the metal circuit plate 3 made of copper so as to block the through-holes 4 provided on the ceramic substrate 1 on the upper and lower surfaces of the ceramic substrate 1 DBC method By being attached , both ends are disposed in the through hole 4 so as to be in contact with the metal circuit boards 3 attached to the upper and lower surfaces of the ceramic substrate 1.
[0050]
If the diameter of the metal column 5 is less than 200 μm, the conduction resistance of the metal column 5 increases, and there is a risk that a large amount of heat is generated due to resistance heating when a large current exceeding 10 A flows. Therefore, the diameter of the metal column 5 is preferably 200 μm or more, preferably 350 μm or more. In particular, if the diameter of the metal column 5 is set to 350 μm or more, even if a large current exceeding 20 A flows through the metal column 5, a large amount of heat due to resistance heat generation is not generated. An electronic component such as a semiconductor element that is bonded and fixed using a material can always be kept at an appropriate temperature, and the electronic component can be operated normally and stably over a long period of time.
[0051]
Furthermore, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.
[0052]
【The invention's effect】
According to the ceramic circuit board of the present invention, there is little pores is located a metal circuit plate which is attached to both surfaces of the ceramic substrate in the through hole of the ceramic substrate, specific resistance of the following metal columns 4Myuomegacm, ends were are placed in contact with the metal circuit plate, since the electrically connected with the metal columns, also occurs the resistance heating in the metal column as a large current of more than 10A on the metal circuit plate and the metal column flows, It does not generate a large amount of heat, and as a result, electronic components such as semiconductor elements that are bonded and fixed onto metal circuit boards using adhesives such as solder are always at the proper temperature, and operate normally and stably over a long period of time. It becomes possible to make it.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of a ceramic circuit board according to the present invention.
FIG. 2 is a cross-sectional view showing another embodiment of the present invention.
FIG. 3 is a cross-sectional view showing another embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Ceramic substrate 2 ... Metallized metal layer 3 ... Metal circuit board 4 ... Through-hole 5 ... Metal pillar 6 ... Active metal brazing material

Claims (1)

The metal columns consisting resistivity in the through-hole causes attached a metal circuit plate so as to close the through-hole on both surfaces of the ceramic substrate from the metallic material 4μΩcm having a through hole, the both ends of the metal circuit board is disposed in contact with the state, the ceramic circuit board, characterized in that it connects the metal circuit plate of the ceramic substrate both sides with the metal column.

Images